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authorManfred Spraul <manfred@colorfullife.com>2014-12-12 16:58:17 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-13 12:42:52 -0800
commit0050ee059f7fc86b1df2527aaa14ed5dc72f9973 (patch)
tree9fa11fd54259ed433d89b0a483e172b8e75d8f23 /ipc/msg.c
parentipc/sem.c: increase SEMMSL, SEMMNI, SEMOPM (diff)
downloadlinux-dev-0050ee059f7fc86b1df2527aaa14ed5dc72f9973.tar.xz
linux-dev-0050ee059f7fc86b1df2527aaa14ed5dc72f9973.zip
ipc/msg: increase MSGMNI, remove scaling
SysV can be abused to allocate locked kernel memory. For most systems, a small limit doesn't make sense, see the discussion with regards to SHMMAX. Therefore: increase MSGMNI to the maximum supported. And: If we ignore the risk of locking too much memory, then an automatic scaling of MSGMNI doesn't make sense. Therefore the logic can be removed. The code preserves auto_msgmni to avoid breaking any user space applications that expect that the value exists. Notes: 1) If an administrator must limit the memory allocations, then he can set MSGMNI as necessary. Or he can disable sysv entirely (as e.g. done by Android). 2) MSGMAX and MSGMNB are intentionally not increased, as these values are used to control latency vs. throughput: If MSGMNB is large, then msgsnd() just returns and more messages can be queued before a task switch to a task that calls msgrcv() is forced. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Rafael Aquini <aquini@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'ipc/msg.c')
-rw-r--r--ipc/msg.c36
1 files changed, 1 insertions, 35 deletions
diff --git a/ipc/msg.c b/ipc/msg.c
index c5d8e3749985..a7261d5cbc89 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -989,43 +989,12 @@ SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
}
-/*
- * Scale msgmni with the available lowmem size: the memory dedicated to msg
- * queues should occupy at most 1/MSG_MEM_SCALE of lowmem.
- * Also take into account the number of nsproxies created so far.
- * This should be done staying within the (MSGMNI , IPCMNI/nr_ipc_ns) range.
- */
-void recompute_msgmni(struct ipc_namespace *ns)
-{
- struct sysinfo i;
- unsigned long allowed;
- int nb_ns;
-
- si_meminfo(&i);
- allowed = (((i.totalram - i.totalhigh) / MSG_MEM_SCALE) * i.mem_unit)
- / MSGMNB;
- nb_ns = atomic_read(&nr_ipc_ns);
- allowed /= nb_ns;
-
- if (allowed < MSGMNI) {
- ns->msg_ctlmni = MSGMNI;
- return;
- }
-
- if (allowed > IPCMNI / nb_ns) {
- ns->msg_ctlmni = IPCMNI / nb_ns;
- return;
- }
-
- ns->msg_ctlmni = allowed;
-}
void msg_init_ns(struct ipc_namespace *ns)
{
ns->msg_ctlmax = MSGMAX;
ns->msg_ctlmnb = MSGMNB;
-
- recompute_msgmni(ns);
+ ns->msg_ctlmni = MSGMNI;
atomic_set(&ns->msg_bytes, 0);
atomic_set(&ns->msg_hdrs, 0);
@@ -1069,9 +1038,6 @@ void __init msg_init(void)
{
msg_init_ns(&init_ipc_ns);
- printk(KERN_INFO "msgmni has been set to %d\n",
- init_ipc_ns.msg_ctlmni);
-
ipc_init_proc_interface("sysvipc/msg",
" key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
IPC_MSG_IDS, sysvipc_msg_proc_show);